1998 Volume 36 Issue 1 Pages 101-110
The purpose of this paper was to elucidate the influence of the reflex control on the jaw-closing muscles during masticatory jaw movements in children with deciduous dentition. The subjects comprised 6 children and 5 adults without any dysfunction of the mandibular movement. Removable bite locks were worn to separate the dental arch into three parts in adults and into two parts in child-rben during tapping movement.
In both adults and children, the activities of the masseter, the anterior and the posterior parts of the temporal muscles were reduced while wearing the incisor bite-block. This was evaluated by the ratio to the muscle activities while wearing total bite-blocks. Each muscle activity was enhanced during tapping when the posterior bite-block was worn. Comparing the ratio of each muscle activity, the masseter muscle showed the most increased activity during the anterior tapping and the posterior part of the temporal muscle showed the most active one during the posterior tapping. These results were more noticeably obtained in children than in adults.
The above results clarified that the periodontal jaw reflex occurring from the anterior and posterior parts of the dentition influenced the activities of the jaw-closing muscles differently during tapping in both adults and children. Moreover, comparing the difference between adults and children, it seems that the activities of the jaw-closing muscles in children are more simply regulated through the jaw reflexes than those in adults during the masticatory jaw movement.
